Preheat your oven to 350°F (175°C). Grease and flour a 9-inch cake pan.
In a medium bowl, whisk together the flour, baking soda, cinnamon, nutmeg, ginger, and salt.
In a large bowl, cream the butter and sugar together until light and fluffy. Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
Gradually add the dry ingredients to the wet ingredients, alternating with the milk. Fold in the diced pears.
Pour the batter into the prepared cake pan and smooth the top. Bake for 50 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.